The Tcpdump Group git mirrors - tcpdump/blob - print-ether.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21 #ifndef lint
  22 static const char rcsid[] =
  23     "@(#) $Header: /tcpdump/master/tcpdump/print-ether.c,v 1.56 2000-09-29 04:58:38 guy Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32 #include <sys/socket.h>
  33
  34 struct mbuf;
  35 struct rtentry;
  36
  37 #include <netinet/in.h>
  38
  39 #include <stdio.h>
  40 #include <pcap.h>
  41
  42 #ifdef INET6
  43 #include <netinet/ip6.h>
  44 #endif
  45
  46 #include "interface.h"
  47 #include "addrtoname.h"
  48 #include "ethertype.h"
  49
  50 #include "ether.h"
  51
  52 const u_char *packetp;
  53 const u_char *snapend;
  54
  55 static inline void
  56 ether_print(register const u_char *bp, u_int length)
  57 {
  58         register const struct ether_header *ep;
  59
  60         ep = (const struct ether_header *)bp;
  61         if (qflag)
  62                 (void)printf("%s %s %d: ",
  63                              etheraddr_string(ESRC(ep)),
  64                              etheraddr_string(EDST(ep)),
  65                              length);
  66         else
  67                 (void)printf("%s %s %s %d: ",
  68                              etheraddr_string(ESRC(ep)),
  69                              etheraddr_string(EDST(ep)),
  70                              etherproto_string(ep->ether_type),
  71                              length);
  72 }
  73
  74 static u_short extracted_ethertype;
  75
  76 /*
  77  * This is the top level routine of the printer.  'p' is the points
  78  * to the ether header of the packet, 'h->tv' is the timestamp,
  79  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  80  * is the number of bytes actually captured.
  81  */
  82 void
  83 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  84 {
  85         u_int caplen = h->caplen;
  86         u_int length = h->len;
  87         struct ether_header *ep;
  88         u_short ether_type;
  89
  90         ts_print(&h->ts);
  91
  92         if (caplen < sizeof(struct ether_header)) {
  93                 printf("[|ether]");
  94                 goto out;
  95         }
  96
  97         if (eflag)
  98                 ether_print(p, length);
  99
 100         /*
 101          * Some printers want to get back at the ethernet addresses,
 102          * and/or check that they're not walking off the end of the packet.
 103          * Rather than pass them all the way down, we set these globals.
 104          */
 105         packetp = p;
 106         snapend = p + caplen;
 107
 108         length -= sizeof(struct ether_header);
 109         caplen -= sizeof(struct ether_header);
 110         ep = (struct ether_header *)p;
 111         p += sizeof(struct ether_header);
 112
 113         ether_type = ntohs(ep->ether_type);
 114
 115         /*
 116          * Is it (gag) an 802.3 encapsulation?
 117          */
 118         extracted_ethertype = 0;
 119         if (ether_type <= ETHERMTU) {
 120                 /* Try to print the LLC-layer header & higher layers */
 121                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 122                         /* ether_type not known, print raw packet */
 123                         if (!eflag)
 124                                 ether_print((u_char *)ep, length);
 125                         if (extracted_ethertype) {
 126                                 printf("(LLC %s) ",
 127                                etherproto_string(htons(extracted_ethertype)));
 128                         }
 129                         if (!xflag && !qflag)
 130                                 default_print(p, caplen);
 131                 }
 132         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 133                 /* ether_type not known, print raw packet */
 134                 if (!eflag)
 135                         ether_print((u_char *)ep, length + sizeof(*ep));
 136                 if (!xflag && !qflag)
 137                         default_print(p, caplen);
 138         }
 139         if (xflag)
 140                 default_print(p, caplen);
 141  out:
 142         putchar('\n');
 143 }
 144
 145 /*
 146  * Prints the packet encapsulated in an Ethernet data segment
 147  * (or an equivalent encapsulation), given the Ethernet type code.
 148  *
 149  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 150  *
 151  * Stuffs the ether type into a global for the benefit of lower layers
 152  * that might want to know what it is.
 153  */
 154
 155 int
 156 ether_encap_print(u_short ethertype, const u_char *p,
 157     u_int length, u_int caplen)
 158 {
 159  recurse:
 160         extracted_ethertype = ethertype;
 161
 162         switch (ethertype) {
 163
 164         case ETHERTYPE_IP:
 165                 ip_print(p, length);
 166                 return (1);
 167
 168 #ifdef INET6
 169         case ETHERTYPE_IPV6:
 170                 ip6_print(p, length);
 171                 return (1);
 172 #endif /*INET6*/
 173
 174         case ETHERTYPE_ARP:
 175         case ETHERTYPE_REVARP:
 176                 arp_print(p, length, caplen);
 177                 return (1);
 178
 179         case ETHERTYPE_DN:
 180                 decnet_print(p, length, caplen);
 181                 return (1);
 182
 183         case ETHERTYPE_ATALK:
 184                 if (vflag)
 185                         fputs("et1 ", stdout);
 186                 atalk_print(p, length);
 187                 return (1);
 188
 189         case ETHERTYPE_AARP:
 190                 aarp_print(p, length);
 191                 return (1);
 192
 193         case ETHERTYPE_IPX:
 194                 ipx_print(p, length);
 195                 return (1);
 196
 197         case ETHERTYPE_8021Q:
 198                 printf("802.1Q vlan#%d P%d%s",
 199                        ntohs(*(u_int16_t *)p) & 0xfff,
 200                        ntohs(*(u_int16_t *)p) >> 13,
 201                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 202                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 203                 p += 4;
 204                 length -= 4;
 205                 caplen -= 4;
 206                 if (ethertype > ETHERMTU)
 207                         goto recurse;
 208
 209                 extracted_ethertype = 0;
 210
 211                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 212                         /* ether_type not known, print raw packet */
 213                         if (!eflag)
 214                                 ether_print(p - 18, length + 4);
 215                         if (extracted_ethertype) {
 216                                 printf("(LLC %s) ",
 217                                etherproto_string(htons(extracted_ethertype)));
 218                         }
 219                         if (!xflag && !qflag)
 220                                 default_print(p - 18, caplen + 4);
 221                 }
 222                 return (1);
 223
 224         case ETHERTYPE_PPPOED:
 225         case ETHERTYPE_PPPOES:
 226                 pppoe_print(p, length);
 227                 return (1);
 228
 229         case ETHERTYPE_LAT:
 230         case ETHERTYPE_SCA:
 231         case ETHERTYPE_MOPRC:
 232         case ETHERTYPE_MOPDL:
 233                 /* default_print for now */
 234         default:
 235                 return (0);
 236         }
 237 }